Due to the Covid-19 pandemic, the intake of vitamin D (VD) has
increased. Vitamin D has multiple regulatory effects in the human body,
including immunological. Evidence accentuates the generation of a
pro-tolerogenic T helper (Th) 2 cell state with VD, suppressing a Th1
inflammatory response. Th2 cell polarization is characteristic of atopy.
However, VD promotes a balanced state through the action of regulatory T
cells, controlling cytokines, both pro-inflammatory and
anti-inflammatory, and by reducing B cell proliferation and
differentiation, thus preventing the development of atopy.